| トップ | Solaris | FreeBSD | Gentoo | CentOS | Fedora | Windows | Tips | 自宅サーバの動作確認 | サイト内検索(Namazu) | サイト内検索(HE) |
ファイルの改竄を検知する為に「Tripwire」を導入する。
インストール時に初期セットアップとデータベースの作成も行われる。
なお、データベースの作成時に大量の Warning が出力されるが、
後でポリシーファイルの設定を行うので特に気にしない。
FreeBSD# cd /usr/ports/security/tripwire <= 作業用ディレクトリへ移動
FreeBSD# make install clean <= 「Tripwire」のインストール
LICENSE AGREEMENT for Tripwire(R) 2.3 Open Source for LINUX
Please read the following license agreement. You must accept the
agreement to continue installing Tripwire.
Press ENTER to view the License Agreement.
<= ライセンスが表示されるのでEnterキーで続行し、Spaceキーで読む
Please type "accept" to indicate your acceptance of this
license agreement. [do not accept] accept <= ライセンスに同意できる場合
Using configuration file install.cfg
Checking for programs specified in install configuration file....
/usr/sbin/sendmail exists. Continuing installation.
/usr/bin/vi exists. Continuing installation.
----------------------------------------------
Verifying existence of binaries...
./bin/i386-unknown-freebsd_r/siggen found
./bin/i386-unknown-freebsd_r/tripwire found
./bin/i386-unknown-freebsd_r/twprint found
./bin/i386-unknown-freebsd_r/twadmin found
This program will copy Tripwire files to the following directories:
TWBIN: /usr/local/sbin
TWMAN: /usr/local/man
TWPOLICY: /usr/local/etc/tripwire
TWREPORT: /var/db/tripwire/report
TWDB: /var/db/tripwire
TWSITEKEYDIR: /usr/local/etc/tripwire
TWLOCALKEYDIR: /usr/local/etc/tripwire
CLOBBER is false.
Continue with installation? [y/n] y <= インストールする
----------------------------------------------
Creating directories...
/usr/local/sbin: already exists
/usr/local/etc/tripwire: created
/var/db/tripwire/report: created
/var/db/tripwire: already exists
/usr/local/etc/tripwire: already exists
/usr/local/etc/tripwire: already exists
/usr/local/man: already exists
/usr/local/share/doc/tripwire: created
----------------------------------------------
Copying files...
/usr/local/share/doc/tripwire/README: copied
/usr/local/share/doc/tripwire/Release_Notes: copied
/usr/local/share/doc/tripwire/COPYING: copied
/usr/local/sbin/tripwire: copied
/usr/local/sbin/twadmin: copied
/usr/local/sbin/twprint: copied
/usr/local/sbin/siggen: copied
/usr/local/share/doc/tripwire/TRADEMARK: copied
/usr/local/share/doc/tripwire/policyguide.txt: copied
/usr/local/etc/tripwire/twpol.txt: copied
/usr/local/man/man5/twpolicy.5: copied
/usr/local/man/man5/twconfig.5: copied
/usr/local/man/man5/twfiles.5: copied
/usr/local/man/man8/siggen.8: copied
/usr/local/man/man8/tripwire.8: copied
/usr/local/man/man8/twadmin.8: copied
/usr/local/man/man8/twintro.8: copied
/usr/local/man/man8/twprint.8: copied
----------------------------------------------
The Tripwire site and local passphrases are used to
sign a variety of files, such as the configuration,
policy, and database files.
Passphrases should be at least 8 characters in length
and contain both letters and numbers.
See the Tripwire manual for more information.
----------------------------------------------
Creating key files...
(When selecting a passphrase, keep in mind that good passphrases typically
have upper and lower case letters, digits and punctuation marks, and are
at least 8 characters in length.)
サイトパスフレーズの設定
Enter the site keyfile passphrase: <= サイトパスフレーズの入力
Verify the site keyfile passphrase: <= サイトパスフレーズの入力（確認）
Generating key (this may take several minutes)...Key generation complete.
(When selecting a passphrase, keep in mind that good passphrases typically
have upper and lower case letters, digits and punctuation marks, and are
at least 8 characters in length.)
ローカルパスフレーズの設定
Enter the local keyfile passphrase: <= ローカルパスフレーズの入力
Verify the local keyfile passphrase: <= ローカルパスフレーズの設定（確認）
Generating key (this may take several minutes)...Key generation complete.
----------------------------------------------
Generating Tripwire configuration file...
----------------------------------------------
Creating signed configuration file...
Please enter your site passphrase: <= サイトパスフレーズの入力
Wrote configuration file: /usr/local/etc/tripwire/tw.cfg
A clear-text version of the Tripwire configuration file
/usr/local/etc/tripwire/twcfg.txt
has been preserved for your inspection. It is recommended
that you delete this file manually after you have examined it.
----------------------------------------------
Customizing default policy file...
----------------------------------------------
Creating signed policy file...
Please enter your site passphrase: <= サイトパスフレーズの入力
Wrote policy file: /usr/local/etc/tripwire/tw.pol
A clear-text version of the Tripwire policy file
/usr/local/etc/tripwire/twpol.txt
has been preserved for your inspection. This implements
a minimal policy, intended only to test essential
Tripwire functionality. You should edit the policy file
to describe your system, and then use twadmin to generate
a new signed copy of the Tripwire policy.
----------------------------------------------
The installation succeeded.
Please refer to /usr/local/share/doc/tripwire/Release_Notes
for release information and to the printed user documentation
for further instructions on using Tripwire 2.3 Open Source for LINUX.
Creating tripwire database
Please enter your local passphrase: <= ローカルパスフレーズの入力
Generating the database...
*** Processing Unix File System ***
### Warning: File system error.
### Filename: /usr/src/sys/compile
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /usr/tmp
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /usr/local/lib/perl5/5.00503/man
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /usr/local/lib/perl5/5.00503/man/man3
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /usr/local/krb5
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /usr/local/krb5/man
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /usr/local/krb5/man/man1
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /usr/local/krb5/man/man2
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /usr/local/krb5/man/man3
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /usr/local/krb5/man/man4
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /usr/local/krb5/man/man5
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /usr/local/krb5/man/man6
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /usr/local/krb5/man/man7
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /usr/local/krb5/man/man8
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /usr/local/krb5/man/man9
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /usr/local/krb5/man/mann
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /usr/local/krb5/man/manl
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /usr/share/man/mann
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /usr/share/perl/man
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /usr/share/perl/man/man3
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /etc/skeykeys
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /.login
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /kernel
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /kernel.old
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /kernel.GENERIC
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /modules
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /modules.old
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /dev/ttyp1
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /dev/ttyp2
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /dev/ttyp3
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /dev/ttyp4
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /dev/ttyp5
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /dev/ttyp6
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /dev/ttyp7
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /dev/ttyp8
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /dev/ttyp9
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /dev/ttypa
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /dev/ttypb
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /dev/ttypc
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /dev/ttypd
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /dev/ttype
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /dev/ttypf
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /dev/ttypg
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /dev/ttyph
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /dev/ttypi
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /dev/ttypj
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /dev/ttypl
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /dev/ttypm
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /dev/ttypn
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /dev/ttypo
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /dev/ttypp
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /dev/ttypq
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /dev/ttypr
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /dev/ttyps
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /dev/ttypt
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /dev/ttypu
### No such file or directory
### Continuing...
### Warning: File system error.
### Filename: /dev/ttypv
### No such file or directory
### Continuing...
Wrote database file: /var/db/tripwire/FreeBSD.crimson-snow.net.twd
The database was successfully generated.
To create a floppy backup of your tripwire database
run "make floppy". The default database will not
fit on a floppy, however with the removal of objects
from the database, it can be made to fit on a 1.44 MB
floppy disk.
The tripwire database, configuration file and
policy file are signed using the local and site keys,
therefore according to the support staff at
tripwiresecurity.com, creating a floppy is not necessary.
===> Compressing manual pages for tripwire-2.3.1.2_5
===> Registering installation for tripwire-2.3.1.2_5
===> Cleaning for libiconv-1.9.2_1
===> Cleaning for gettext-0.14.5
===> Cleaning for gmake-3.80_2
===> Cleaning for libtool-1.5.20
===> Cleaning for gcc-2.95.3_2
===> Cleaning for tripwire-2.3.1.2_5
|
テキスト版の設定ファイルを編集する。
FreeBSD# vi /usr/local/etc/tripwire/twcfg.txt <= 設定ファイルの編集 REPORTFILE =/var/lib/tripwire/report/$(HOSTNAME)-$(DATE).twr ↓ REPORTFILE =/var/lib/tripwire/report/$(HOSTNAME).twr <= レポートファイル名を変更 LOOSEDIRECTORYCHECKING =false ↓ LOOSEDIRECTORYCHECKING =true <= ファイル変更検知時に所属ディレクトリまで変更検知しない MAILNOVIOLATIONS =true ↓ MAILNOVIOLATIONS =false <= ファイル変更検知時のみメールを送信する EMAILREPORTLEVEL =3 ↓ EMAILREPORTLEVEL =4 <= ファイル変更チェック結果レポートレベルの変更 REPORTLEVEL =3 ↓ REPORTLEVEL =4 <= ファイル変更チェック結果レポートレベルの変更 |
設定ファイルの暗号化
FreeBSD# twadmin --create-cfgfile -S /usr/local/etc/tripwire/site.key /usr/local/etc/tripwire/twcfg.txt <= 暗号化した設定ファイルの作成（テキスト版=>暗号署名版） Please enter your site passphrase: <= サイトパスフレーズ入力 Wrote configuration file: /usr/local/etc/tripwire/tw.cfg FreeBSD# rm -f /usr/local/etc/tripwire/twcfg.txt <= テキスト版の設定ファイルの削除 ・暗号化されたファイルから設定ファイル（テキスト版）を作成する場合 FreeBSD# twadmin --print-cfgfile > /usr/local/etc/tripwire/twcfg.txt |
ポリシーファイルの作成
デフォルトのポリシーファイルでは存在しないファイルのチェックが有効であったり、
存在するファイルのチェックが無効になっている。
そこで、和泉宏明氏の作成された
Perlスクリプトを利用し、
ポリシーファイルを作成する。
なお、wgetを用いているが、導入していない場合、portsよりインストールする。
wgetの場所は /usr/ports/ftp/wget になる。
FreeBSD# wget http://www.aritia.org/hizumi/linux/tripwire_pol.pl.txt <= スクリプトファイルの取得
FreeBSD# mv tripwire_pol.pl.txt /usr/local/etc/tripwire/tripwire_pol.pl <= スクリプトファイルを移動
FreeBSD# chmod 700 /usr/local/etc/tripwire/tripwire_pol.pl <= スクリプトファイルに実行権限付加
FreeBSD# view /usr/local/etc/tripwire/tripwire_pol.pl <= Perlスクリプトの確認
#!/usr/bin/perl
# Tripwire Policy File customize tool for Redhat 8.0
# ----------------------------------------------------------------
# Copyright (C) 2003 Hiroaki Izumi
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
# ----------------------------------------------------------------
# Usage:
# perl tripwire_pol.pl {Pol file}
# --------------------------------------------------------
#
$POLFILE=$ARGV[0];
open(POL,"$POLFILE") or die "open error: $POLFILE" ;
my($myhost,$thost) ;
my($sharp,$tpath,$cond) ;
my($INRULE) = 0 ;
while (<POL>) {
chomp;
if (($thost) = /^HOSTNAMEs*=\s*(.+)\s*;/) {
$myhost = `hostname` ; chomp($myhost) ;
if ($thost ne $myhost) {
$_="HOSTNAME=$myhost;" ;
}
}
elsif ( /^{/ ) {
$INRULE=1 ;
}
elsif ( /^}/ ) {
$INRULE=0 ;
}
elsif ($INRULE == 1 and ($sharp,$tpath,$cond) = /^(\s*\#?\s*)(\/\S+)\b(\s+->\s+.+)$/) {
$ret = ($sharp =~ s/\#//g) ;
if ($tpath eq '/sbin/e2fsadm' ) {
$cond =~ s/;\s+(tune2fs.*)$/; \#$1/ ;
}
if (! -e $tpath) {
$_ = "$sharp#$tpath$cond" if ($ret == 0) ;
}
else {
$_ = "$sharp$tpath$cond" ;
}
}
print "$_\n" ;
}
close(POL) ;
FreeBSD# /usr/local/etc/tripwire/tripwire_pol.pl /usr/local/etc/tripwire/twpol.txt > /usr/local/etc/tripwire/twpol.txt.tmp
<= デフォルトのポリシーファイルを基にポリシーファイル作成
FreeBSD# rm -f /usr/local/etc/tripwire/twpol.txt <= デフォルトのポリシーファイルを削除
FreeBSD# mv /usr/local/etc/tripwire/twpol.txt.tmp /usr/local/etc/tripwire/twpol.txt
<= 作成したポリシーファイルをデフォルトのポリシーファイル名にリネーム
|
ポリシーファイルの設定
全てのファイル変更チェックの結果をroot宛にメールを送信するようにする。
FreeBSD# vi /usr/local/etc/tripwire/twpol.txt <= 設定ファイルの作成
( emailto = root ) <= 追加
{ <= 追加
# Tripwire Binaries
{
/etc/group -> $(SEC_CRIT) ;
/etc/crontab -> $(SEC_CRIT) ;
}
} <= 追加
#=============================================================================
|
ポリシーファイルの暗号化
FreeBSD# twadmin --create-polfile -S /usr/local/etc/tripwire/site.key /usr/local/etc/tripwire/twpol.txt <= 暗号化したポリシーファイルの作成（テキスト版=>暗号署名版） Please enter your site passphrase: <= サイトパスフレーズ入力 Wrote policy file: /usr/local/etc/tripwire/tw.pol FreeBSD# rm -f /usr/local/etc/tripwire/twpol.txt <= ポリシーファイル（テキスト版）を削除 ・暗号化されたファイルからポリシーファイル（テキスト版）を作成する場合 FreeBSD# twadmin --print-polfile > /usr/local/etc/tripwire/twpol.txt |
ポリシーファイルよりデータベースを作成する。
FreeBSD# tripwire --init <= データベースの作成 Please enter your local passphrase: <= ローカルパスフレーズ入力 Parsing policy file: /usr/local/etc/tripwire/tw.pol Generating the database... *** Processing Unix File System *** Wrote database file: /var/db/tripwire/FreeBSD.crimson-snow.net.twd The database was successfully generated. |
ここで Warning が出力され、 No such file or directory と出力された場合、
ポリシーファイルの該当行をコメントアウトする。
自分の環境では以下の２行に Warning が出力された為、コメントアウトした。
FreeBSD# twadmin --print-polfile > /usr/local/etc/tripwire/twpol.txt <= 暗号化されたファイルからポリシーファイル（テキスト版）を作成する FreeBSD# vi /usr/local/etc/tripwire/twpol.txt <= ポリシーファイルの編集 $(TWPOL)/twcfg.txt -> $(SEC_BIN) ; $(TWPOL)/twpol.txt -> $(SEC_BIN) ; ↓ # $(TWPOL)/twcfg.txt -> $(SEC_BIN) ; <= コメントアウト # $(TWPOL)/twpol.txt -> $(SEC_BIN) ; <= コメントアウト |
コメントアウト後、上記の
ポリシーファイルの暗号化
の作業を行い、再度データベースを作成する。FreeBSD# rm -f /var/db/tripwire/FreeBSD.crimson-snow.net.twd <= データベースの削除 |
FreeBSD# tripwire --check <= ファイル変更チェック
Parsing policy file: /usr/local/etc/tripwire/tw.pol
*** Processing Unix File System ***
Performing integrity check...
Wrote report file: /var/db/tripwire/report/FreeBSD.crimson-snow.net.twr
Tripwire(R) 2.3.0 Integrity Check Report
Report generated by: root
Report created on: Mon Oct 16 23:15:29 2005
Database last updated on: Never
===============================================================================
Report Summary:
===============================================================================
Host name: FreeBSD.crimson-snow.net
Host IP address: 127.0.0.1
Host ID: None
Policy file used: /usr/local/etc/tripwire/tw.pol
Configuration file used: /usr/local/etc/tripwire/tw.cfg
Database file used: /var/db/tripwire/FreeBSD.crimson-snow.net.twd
Command line used: tripwire --check
===============================================================================
Rule Summary:
===============================================================================
-------------------------------------------------------------------------------
Section: Unix File System
-------------------------------------------------------------------------------
Rule Name Severity Level Added Removed Modified
--------- -------------- ----- ------- --------
Invariant Directories 66 0 0 0
* Tripwire Data Files 100 1 0 0 <= Tripwire Data Filesに1件の追加を検出
Temporary directories 33 0 0 0
Local files 100 0 0 0
Tripwire Binaries 100 0 0 0
System Administration Programs 100 0 0 0
User Utilities 100 0 0 0
Libraries, include files, and other system files
100 0 0 0
X11R6 100 0 0 0
Sources 100 0 0 0
(/usr/src)
NIS 100 0 0 0
(/var/yp)
/etc 100 0 0 0
Security Control 100 0 0 0
Root's home 100 0 0 0
FreeBSD Kernel 100 0 0 0
(/boot)
/dev 100 0 0 0
Linux Compatibility 100 0 0 0
(/compat)
Total objects scanned: 90112
Total violations found: 1
===============================================================================
Object Summary:
===============================================================================
-------------------------------------------------------------------------------
# Section: Unix File System
-------------------------------------------------------------------------------
-------------------------------------------------------------------------------
Rule Name: Tripwire Data Files (/var/db/tripwire)
Severity Level: 100
-------------------------------------------------------------------------------
Added:
"/var/db/tripwire/FreeBSD.crimson-snow.net.twd.bak" <= /var/db/tripwire/FreeBSD.crimson-snow.net.twd.bakの追加を検出
(Tripwireのデータベースの為、問題無し)
===============================================================================
Error Report:
===============================================================================
No Errors
-------------------------------------------------------------------------------
*** End of report ***
Tripwire 2.3 Portions copyright 2000 Tripwire, Inc. Tripwire is a registered
trademark of Tripwire, Inc. This software comes with ABSOLUTELY NO WARRANTY;
for details use --version. This is free software which may be redistributed
or modified only under certain conditions; see COPYING for details.
All rights reserved.
Integrity check complete.
|
「Tripwire」を実行するスクリプトを作成し、cronに登録して自動実行するようにする。
FreeBSD# vi tripwire.sh <= スクリプトの作成 #!/bin/sh # 設定 TRIPWIRE=/usr/local/sbin/tripwire TWADMIN=/usr/local/sbin/twadmin TRIPWIRE_POL=/usr/local/etc/tripwire/tripwire_pol.pl LOG=/var/log/tripwire.log LOCALPASS=ローカルパスフレーズ <= ローカルパスフレーズを入力 SITEPASS=サイトパスフレーズ <= サイトパスフレーズを入力 # Tripwire実行 $TRIPWIRE --check --email-report > $LOG # ポリシーファイル最新化 $TWADMIN --print-polfile > /usr/local/etc/tripwire/twpol.txt $TRIPWIRE_POL /usr/local/etc/tripwire/twpol.txt > /usr/local/etc/tripwire/twpol.txt.tmp $TWADMIN --create-polfile -S /usr/local/etc/tripwire/site.key -Q $SITEPASS /usr/local/etc/tripwire/twpol.txt.tmp >> $LOG rm -f /usr/local/etc/tripwire/twpol.* # データベース最新化 rm -f /var/db/tripwire/FreeBSD.crimson-snow.net.twd $TRIPWIRE --init -P $LOCALPASS >> $LOG FreeBSD# chmod 700 /root/tripwire.sh <= 作成したスクリプトに実行権限付加 |
スクリプトの自動実行
FreeBSD# vi /etc/crontab <= 設定ファイルの編集 00 03 * * * root /root/tripwire.sh <= 追加(毎日6:00にスクリプト実行) |